Astrophysics Webinar
Probing the Universe’s First Billion Years with hydrogen 21-cm radiation
Speaker: Raghunath Ghara (Department of Natural and Life Sciences, The Open University of Israel)
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Abstract
The redshifted 21-cm signal from the intergalactic medium (IGM) neutral hydrogen is the most promising probe of the Epoch of Reionization. It has the ability to reveal many of unknown facts about this epoch such as properties of the early sources of radiation, thermal and ionization states of the IGM. Radio telescopes such as LOFAR, MWA, HERA are providing stronger upper limits on the 21-cm power spectrum. I will be talking about this probe and how these measurements are used to infer the states of the IGM as well as the properties of the first sources that formed during that period.
Short Biography
Raghunath Ghara is a post-doctoral fellow at the Department of Natural and Life Sciences, The Open University of Israel, Israel. His previous academic records are as follows. He completed his B.Sc. course in 2009 at the Ramakrishna Mission Residential College, University of Calcutta, India. Thereafter he joined Harish-Chandra Research Institute (HRI), Allahabad as an integrated Ph.D. student. He completed his M.Sc. course from HRI and received a degree from Homi Bhabha National Institute (HBNI), Mumbai, India. Thereafter he moved to National Centre for Radio Astrophysics (NCRA-TIFR), Pune, India with his Ph.D. supervisor Dr. Tirthankar Roy Choudhury. He completed his Ph.D. from NCRA-TIFR in Physics in October 2016. Thereafter he joined Prof. Garrelt Mellema's group in the Department of Astronomy, Stockholm University, Sweden as a post-doctoral fellow and worked until October 2019. Afterward, he moved to Technion, Haifa, Israel to work with Prof. Saleem Zaroubi's group as a postdoc fellow and worked there for two years before he moved to the Open University in Ra'anana, Israel. His research focuses on the theoretical studies of first source formation in the Universe, ways to detect those faint primordial sources, impacts of these sources on the intergalactic medium (IGM), etc. These primordial sources changed the ionization and thermal states of the IGM during the Cosmic Dawn and Epoch of Reionization. In other words, his research aims to probe the physical states of the first billion years of our Universe.